Multi-piece golf club heads formed from titanium and zirconium alloys

ABSTRACT

A golf club head and a method for forming a golf club head are disclosed. The golf club head may include multiple components with varying densities to manipulate the weight, volume, and properties of the golf club head.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 13/615,816, filed Sep. 14, 2012, now U.S. Pat. No. 8,876,632,the entire disclosure of which is incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to a golf club head comprising materialsdesigned to provide specific densities for use in various parts of theclub head to achieve maximum volume within specific weight goals. Morespecifically, the present invention relates to a golf club head withproperties that may be manipulated based on the low and high densitymaterials.

BACKGROUND OF THE INVENTION

Various design parameters affect the performance of a wood-type golfclub (e.g., drivers, fairway woods, and hybrids). Accordingly, golfequipment designers are constantly manipulating the shape, size, andmaterials used to manufacture clubs and balls.

For example, as golf club heads have increased in volume, their momentsof inertia have also increased. Indeed, a larger moment of inertia,which is the resistance to twisting of any golf club head when the golfball is impacted off center, provides what manufacturers refer to a“larger sweet spot” and results in more forgiveness on off-center hits.However, when the volume of a golf club head is maximized throughspatially distributing the mass in all three orthogonal orientations,the center of gravity of the golf club head is positioned substantiallyrearward from the front face of the golf club head, which renders shotsstruck off-center from the sweet spot of the golf club head undesirableas a result of the side-spin or backspin.

In some instances, one or more weight members attached to the golf clubhead may be positioned to manipulate the center of gravity. Alternately,manufacturers have attempted to manipulate the distribution of theamount of material in various parts of the head to strike a balancebetween the moment of inertia and center of gravity. Adding weight tocertain areas of a golf club head, however, may cause it to become heavyand unwieldy, possibly to the point of limiting a golfer's swing speedand adversely affecting the golfer's swing mechanics. Similarly,manipulating the distribution of material may result in a club head thatcannot withstand the stress of repeated impacts with a golf ball thatoccur during normal use of the resulting golf club.

Designers have also attempted to manipulate the weight distribution ofthe club head using low and high density materials, although low densitymaterials are typically only been placed in non-critical areas or lowimpact areas. In addition, attempts to manipulate the weightdistribution of the club head using low and high density materials aresomewhat limited by the process, e.g., the thickness/thinness of thecasting. For example, a widely used material for wood-type golf clubheads is titanium alloy. The alloy is available for casting and inwrought sheet form, but because the mechanical properties of the castmaterial are inferior to the wrought material, the thickness of the castmaterial must be greater than the wrought material for maximumperformance. Accordingly, the weight reduction in non-critical areas ofthe club head is limited to the thickness/thinness that can be achievedwith the specific material used and the casting process rather than themechanical properties of the alloy material.

With regard to fairway woods, which have a smaller profile than driversbut larger profile than hybrids, if conventional titanium alloys areused to make the fairway wood golf club head, the low density of thematerial requires additional weights to be added to meet the requiredmass. Thus, most manufacturers use stainless steel for the body andtitanium for the face. However, this is not ideal because thecombination of materials yields two discrete densities and limits thedesign options.

Therefore, there is a continuing need for wood-type golf club heads (andmethods of manufacturing such heads) that have high strength faces andbodies made from metal alloys with densities that can be tailoreddepending on the shape, size, and performance requirements of theparticular club head. Accordingly, the present invention provides amethod of making a golf club head (and the resulting golf club head)that includes multiple materials to achieve the proper balance betweenmass distribution and club head performance.

SUMMARY OF THE INVENTION

The present invention is directed to a golf club head, including: afirst portion including a body defining an inner volume, sole, and askirt, wherein the first portion is formed from a first titanium alloyhaving a first density ranging from about 4 g/cm³ to about 5 g/cm³; asecond portion including a crown, wherein the second portion is formedfrom a second titanium alloy having a second density ranging from about4 g/cm³ to about 5 g/cm³; and a third portion including a face, whereinthe third portion is formed from a third titanium alloy having a thirddensity ranging from about 4 g/cm³ to about 5 g/cm³.

In one embodiment, the second density is different from the firstdensity. In another embodiment, the third density is greater than thefirst and second densities. The first titanium alloy may includeTi-8Al-1V-1Mo. In still another embodiment, the second titanium alloyincludes Ti-5Al-1Fe-1Cr-0.7Mo.

The golf club head may include at least one weight and/or at least onecorresponding weight port. In one embodiment, the volume of the clubhead volume is between about 300 cc and about 460 cc.

The present invention is also related to a golf club head, including: afirst portion including a body defining an inner volume, a sole, acrown, and a skirt, wherein the first portion includes a first materialhaving a first density and a first weight, wherein the first materialincludes an alloy including titanium, zirconium, or a combinationthereof, and wherein the first density ranges from about 7 g/cm³ toabout 8.5 g/cm³; and a second portion including a face, wherein thesecond portion includes a second material having a second density lessthan the first density, wherein the second density is at least about 30percent less than the first density.

In one embodiment, the first material includes a binarytitanium-zirconium alloy. In another embodiment, the binarytitanium-zirconium alloy includes about 25 percent to about 75 percentby weight Zr. In still another embodiment, the binary titanium-zirconiumalloy includes about 10 percent to about 19 percent by weight Zr. Thesecond density may range from about 4 g/cm³ to about 5.5 g/cm³.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention can be ascertained fromthe following detailed description that is provided in connection withthe drawings described below:

FIG. 1 shows a top view of one embodiment of a golf club head accordingto the present invention;

FIG. 2 shows a top view of one embodiment of a golf club head accordingto the present invention;

FIG. 3 shows a side view of one embodiment of a golf club head accordingto the present invention; and

FIG. 4 shows a rear perspective view of one embodiment of a golf clubhead according to the present invention; and

FIG. 5 shows a top view of one embodiment of a golf club head accordingto the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates to wood-type golf club heads, golf clubs,and the like (such as drivers, fairway woods, hybrids, and/or the like),as well as to methods of making and using such clubs and club heads. Theclub head body member may take on a variety of different forms, shapes,and/or sizes without departing from this invention and includes, but isnot limited to, a club head body member defining an interior chamber, astriking face, a crown portion, and a sole portion.

The club head may be made of a one piece construction or from amulti-piece construction. In a multi-piece construction, the club headbody member is made from multiple components that are joined togethervia welding, brazing, adhesive bonding, or combinations thereof In oneembodiment, a club head body member includes two components that arejoined together: (1) a club head body member defining an interiorchamber without the striking face or a club head body member without thecrown. In another embodiment, the club head body member is formed from aplurality of components including, but not limited to, a face insert, acrown, and a body (which includes the sole and a skirt). The club headbody member may include two components, three components, fourcomponents, five components, six components, or more than sixcomponents.

While the overall weight of the wood-type golf club head of theinvention will vary depending on the specific type, i.e., driver,fairway wood, hybrid, the use of the materials described herein and themethods of forming the golf club heads of the invention provide amanufacturer the ability to maximize volume and adjust MOI and COG bystrategically distributing the materials in different components of theclub head. For example, even though a driver will always be designed toweigh between about 190 g and 205 g, the specific materials used in thegolf club head allow the maximum volume and strength with adjustabilityin the MOI and COG. In fact, the relatively low density of titanium,which is 56 percent that of steel and half that of nickel and copperalloys, translates into twice as much metal volume per weight. Inaddition, the alloys of the present invention offer useful resistance tosignificantly larger ranges of chemical environments and temperaturescompared to other materials including stainless steels and aluminum-,copper-, and nickel-based alloys.

Low Density Titanium Alloys for a Multi-Component Club Head

In one aspect of the invention, the club head is formed from a pluralityof components, each component being formed from a different low densitytitanium alloy with a resulting reduction in the overall weight of theclub head as compared to a club head formed from conventional materials.In one embodiment, the club head is formed from at least threecomponents, each formed with a different low density titanium alloy. Inparticular, the club head in this aspect of the invention may includethree components: a club head body member, a crown, and a face insert.In another embodiment, the club head is formed from at least fourcomponents, each formed from a different low density titanium alloy. Forexample, the club head in this aspect of the invention may include fourcomponents: a club head body member, a crown, a sole, and a face insert.

Materials

A number of low density titanium alloys are suitable for forming thevarious components of the club head body member according to this aspectof the invention. Suitable low density titanium alloys include, but arenot limited to, alpha or near-alpha titanium alloys such asTi-8Al-1V-1Mo, Ti-5Al-1Fe-1Cr-0.7Mo, alpha-beta alloys such as Ti-6Al-4V(Ti-6-4), Ti-4.5Al-3V-2Fe-2Mo (SP-700), and Ti-5Al-1Sn-1Zr-1V-0.8Mo(Ti-5111), and heat treated beta alloys such as Ti-15-3-3-3, Beta C, DAT51, DAT 55. Other suitable titanium alloys include alpha and near-alphaalloys such as Ti-0.3Mo-0.8Ni, Ti-3Al-2.5V, Ti-3Al-2.5V-Pd,Ti-3Al-2.5V-Ru, Ti-5Al-2.5Sn, Ti-5Al-2.5Sn ELI, Ti-8Al-1Mo-1V, andTi-6Al-2Sn-4Zr-2Mo-0.1Si, alpha-beta alloys such as Ti-6Al-4V ELI,Ti-6Al-4V-0.1Ru, Ti-6Al-7Nb, Ti-6Al-6V-2Sn, Ti-6Al-2Sn-4Zr-6Mo,Ti-4Al-4Mo-2Sn-0.5Si, Ti-6Al-2Sn-2Zr-2Mo-2Cr-0.15Si, andTi-5Al-4Cr-4Mo-2Sn-2Zr, Ti-4Al-2.5V-1.5Fe, Ti-4Al-2Mo-2V-0.5Fe,Ti-6Al-1.5V-1.5Mo-0.3Fe, Ti-5Al-4V-1Mo-0.5Fe, beta and near-beta alloyssuch as Ti-10V-2Fe-3Al, Ti-3Al-8V-6Cr-4Zr-4Mo, andTi-3Al-8V-6Cr-4Zr-4Mo-0.05Pd, Ti-15V-3Cr-3Sn-3Al, Ti-15Mo-5Zr-3Al,Ti-15Mo-3Al, Ti-5Al-5V-5Mo-3Cr, Ti-5.5Al-5Mo-5V-2.2Cr-0.8Fe, andmixtures thereof.

Method of Forming

One method of forming a golf club head according to this aspect of theinvention includes a first step of casting a club head body member froma first titanium alloy leaving the crown open. Alternatively, the firststep includes casting a club head body member from a first titaniumalloy leaving the face open. While the specific embodiment providedbelow contemplates three components, each formed form a differenttitanium alloy, one of ordinary skill in the art would appreciate thatthe present invention extends to embodiments where the club head bodymember is further separated into multiple components, e.g., a sole, askirt, and the like, each of which may be formed from different titaniumalloys.

The first titanium alloy may have a density ranging from 3.5 g/cm³ toabout 5.5 g/cm³. In one embodiment, the density of the first titaniumalloy is about 4.0 g/cm³ to about 5.0 g/cm³. According to one aspect ofthe invention, the first titanium alloy has a density of about 4.2 g/cm³to about 4.6 g/cm³. For example, the density of the first titanium alloymay be about 4.3 g/cm³ to about 4.4 g/cm³. In one embodiment, the firsttitanium alloy is Ti-8Al-1V-1Mo.

The thickness of the club head body member may be from about 0.1 mm toabout 1.0 mm. In one embodiment, the thickness of the club head bodymember is about 0.2 mm to about 0.8 mm. In still another embodiment, thethickness of the club head body member is about 0.4 mm to about 0.6 mm.In yet another embodiment, the thickness of the club head body member isabout 0.5 mm.

After the club head body member is cast, the remaining portion not leftopen is cut out. For example, if the crown was left open in the firststep, the face is cut out and, in the alternative, if the face was leftopen, the crown is cut out. The crown is then stamped out from a secondtitanium alloy. The second titanium alloy has a density different thanthe first and third titanium alloys used to form the club head bodymember and the face insert. In one embodiment, the second titanium alloyhas a density that is greater than the first titanium alloy. The secondtitanium alloy may have a density ranging from 3.5 g/cm³ to about 5.5g/cm³. In one embodiment, the density of the second titanium alloy isabout 4.0 g/cm³ to about 5.0 g/cm³. According to one aspect of theinvention, the second titanium alloy has a density of about 4.2 g/cm³ toabout 4.8 g/cm³. For example, in one embodiment, the second titaniumalloy has a density of about 4.5 g/cm³ to about 4.8 g/cm³.

In one embodiment, the second titanium alloy is selected from the groupconsisting of Ti-5Al-1Fe-1Cr-0.7Mo, Ti-15Mo-5Zr, Ti-15Mo-5Zr-3, Ti-17,Ti-4Al-2.5V-1.5Fe, Ti-5Al-4V-0.6Mo-0.4Fe, Ti-5V-5Mo-5Al-3Cr-0.5Fe, andTi-5V-5Mo-5Al-1Cr-1Fe-1Zr. In another embodiment, the second titaniumalloy is Ti-5Al-1Fe-1Cr-0.7Mo.

The thickness of the crown may be from about 0.1 mm to about 1.0 mm. Inone embodiment, the thickness of the crown is about 0.2 mm to about 0.8mm. In still another embodiment, the thickness of the crown is about 0.4mm to about 0.6 mm. In yet another embodiment, the thickness of thecrown is about 0.5 mm.

The face insert may be formed from a third titanium alloy. The thirdtitanium alloy may have a density ranging from 3.5 g/cm³ to about 5.5g/cm³. In one embodiment, the density of the third titanium alloy isabout 4.0 g/cm³ to about 5.0 g/cm³. According to one aspect of theinvention, the third titanium alloy has a density of about 4.2 g/cm³ toabout 4.6 g/cm³. In one embodiment, the third titanium alloy has adensity greater than the first and second titanium alloys. In anotherembodiment, the third titanium alloy has a density greater than thedensity of the first titanium alloy, but less than the density of thesecond titanium alloy.

In one embodiment, the third titanium alloy is selected from the groupconsisting of Ti-6-4, SP-700, Ti-5111, and TCX11. In another embodiment,the third titanium alloy is selected from the group consisting ofTi-15-3-3-3, Beta C, DAT 51, and DAT 55. In yet another embodiment, theface insert is formed from two or more components, each component formedfrom a different titanium alloy selected from the group consisting ofTi-6-4, SP-700, Ti-15-3-3-3, Beta C, DAT 51, and DAT 55.

The crown and face inserts may be joined together with the club headbody member (in the respective cavities) via welding, infrared brazing,adhesive bonding, or combinations thereof. In one embodiment, the crownand face inserts are joined to the club head body member via welding.The type of welding used to join each insert to the club head bodymember may be the same for both inserts or different. As would beappreciated by those of ordinary skill in the art, the type of weldingused to join the components together may be any suitable welding thatresults in a joined product with the least weld material at the jointsand heat affected zones. In this aspect, suitable types of welding foruse with the present invention include, but are not limited to, laserwelding, plasma welding, TIG welding, MIG welding, or combinationsthereof In one embodiment, the type of welding used to join either orboth of the crown and face components may be laser welding, plasmawelding, or combinations thereof Without being bound to any specifictheory, laser and plasma welding reduces the amount of material added atthe joint and result in smaller heat affected zones (as compared to TIGwelding).

FIG. 1 shows a portion of a golf club head 10 of the present invention.In the illustrated embodiment, the club head body member 20 is formedfrom a first low density titanium alloy. The crown 30 is formed form asecond low density titanium alloy. The face insert 40 is formed from athird low density titanium alloy. In one embodiment, the club head bodymember 20 is further separated into components. For example, as shown inFIG. 2, the club head body member 20 has a face 22, a skirt 24, and asole 26, which are all formed as separate pieces from different titaniumalloys. In such an embodiment, the components may be coupled to eachother in a variety of manners with welding being one preferred manner.In FIGS. 1 and 2, the hosel and shaft are shown, but not considered tobe part of the club head body member.

FIG. 3 shows another embodiment of the invention where the club headbody member 20 is formed from separate components. In particular, theclub head body member includes a skirt 24, a skirt portion 25, a sole26, a sole portion 28, a crown 30, and a face insert 40. In this aspectof the invention, the skirt 24 and sole 26 are formed as part of theclub head body member, but the skirt portion 25 and sole portion 28 areformed from titanium alloys that differ from the titanium alloys thatare used to form the club head body member 20. The face insert 40 isalso formed form a different titanium alloy than the club head bodymember. The crown 30 may be formed form the same or different titaniumalloy than the club head body member.

In FIG. 4, a rear view of a club head shows a club head body member 20that is formed from a first titanium alloy and includes the crown 30 andsole 26. A second titanium alloy is used to form the skirt portion 25and a third titanium alloy is used to form the face insert 40.

Low Modulus, High Density Alloys for a Multi-Component Club Head

In another aspect of the invention, a club head is formed from lowspecific modulus materials with densities similar to stainless steel.For example, the density of steel typically varies based on the alloyingconstituents but usually ranges between about 7.75 g/cm³ and 8.05 g/cm³.While using steel in fairway woods generally provides a desirable massdistribution for the smaller head head size, the smaller size of theface makes it difficult to achieve maximum coefficient of restitutionwhen using stainless steel because the face must remain a certainthickness in order not to compromise the durability. However, iftitanium alloys are used to make the fairway wood, the lower modulus ofthe material increases the COR of the club head, but the low density ofthe titanium alloy requires the use of weights to achieve the desiredmass. In the past, manufacturers have attempted to balance the benefitsof both materials in fairway woods with the use of a titanium face and asteel body. The present invention provides a solution to the issue witha high strength titanium face and a club head body member formed fromtitanium or zirconium alloys or both that achieves weight targets in therange of 180 g to 220 g, while still maximizing the internal massdistribution and volume of the club head. In addition, because titaniumalloys and zirconium alloys are compatible with titanium and titaniumalloys, the joining of the club head body member with the face isfacilitated.

Materials

In this aspect of the invention, suitable materials for use in formingthe club head body member include, but are not limited to, binary,tertiary, and higher titanium and zirconium alloys such as Ti-Zr, Ti-Hf,Ti-Mo, Ti-V, Ti-Ta, Ti-Nb, Ti-Cr, Zr-W, Zr-Hf, and Zr-Ta. As would beappreciated by one of ordinary skill in the art, zirconium and hafniummay be alloyed with titanium in any proportion while still maintaining asingle phase based on their isomorphous nature. Likewise, zirconium isisomorphous with hafnium and, thus, Zr-Hf alloys may be made by melting.

The densities of the titanium and zirconium alloys for use in formingthe club head body member (or portions thereof) may range from about 6g/cm³ to about 9 g/cm³. In one embodiment, the density of the materialused to form the golf club head body member (or portions thereof) rangesbetween about 6.5 g/cm³ and 8 g/cm³. In another embodiment, the densityof the material used to form the golf club head body member (or portionsthereof) ranges from about 6.75 g/cm³ to about 7.75 g/cm³. Suitablealloys that may be used to achieve such densities include, but are notlimited to, Zr-5W, Zr-6Ta, Zr-7Hf, Zr-10Mo, Zr-16Nb, and combinationsthereof.

Method of Forming

One method of forming a golf club head according to this aspect of theinvention includes a first step of casting a club head body member froma first titanium or zirconium alloy leaving the face open. While thespecific embodiments provided below contemplates two and threecomponents, each formed from a different material, one of ordinary skillin the art would appreciate that the present invention extends toembodiments where the club head body member is further separated intomultiple components, e.g., a sole, a skirt, and the like, each of whichmay be formed from different materials.

The first material may have a density ranging from 6.0 g/cm³ to about9.0 g/cm³. In one embodiment, the density of the first material is about7.0 g/cm³ to about 8.5 g/cm³. According to one aspect of the invention,the first material has a density of about 7.5 g/cm³ to about 8.1 g/cm³.For example, the density of the first material may be about 7.6 g/cm³ toabout 8.05 g/cm³.

In one embodiment, the first material is a binary titanium alloy, suchas Ti-Zr, Ti-Hf, Ti-Mo, Ti-Ta, Ti-Nb, Ti-Cr. For example, the firstmaterial may be Ti-Hf, Ti-Mo, Ti-Ta, Ti-Nb, and combinations thereof. Inanother embodiment, the first material may be Ti-Zr, Ti-Cr, andcombinations thereof. In yet another embodiment, the first material is abinary zirconium alloy such as Zr-W, Zr-Hf, and Zr-Ta. In this aspect ofthe invention, the first material may be a binary alloy that is meltedfrom technically pure metals.

In one embodiment, the first material may be a binary titanium-zirconiumalloy that includes about 25 percent to about 75 percent by weightzirconium. The density range for these two alloys preferably ranges fromabout 4.9 g/cm³ to 5.81 g/cm³. In another embodiment, the first materialmay be a binary titanium-zirconium alloy that includes less than about25 percent by weight (14.9 atomic percent) but more than 5 percent byweight (2.7 atomic percent) zirconium, resulting in a titanium-richalloy. For example, the first material may be a binarytitanium-zirconium alloy that includes about 10 percent to about 19percent by weight zirconium. In one embodiment, the first material is abinary titanium-zirconium alloy that includes 13 percent to 17 percentby weight zirconium. In addition to Ti and Zr, may include about 0.09 toabout 0.11 percent oxygen and about 0.02 to about 0.03 percent nitrogen.

In yet another embodiment, the first material is a higher titanium-richalloy that comprises Ti-Zr-6Al-4V.

The thickness of the club head body member may be from about 0.1 mm toabout 1.0 mm. In one embodiment, the thickness of the club head bodymember is about 0.2 mm to about 0.8 mm. In still another embodiment, thethickness of the club head body member is about 0.4 mm to about 0.6 mm.In yet another embodiment, the thickness of the club head body member isabout 0.5 mm.

After the club head body member is cast, one embodiment contemplatescutting out the crown so that a different material may be used for thecrown. In this aspect of the invention, the crown may be stamped outfrom a second material that is different from the first material but hasa similar density range. For example, the second material may be a highdensity material ranging from 6.0 g/cm³ to about 9.0 g/cm³. In oneembodiment, the density of the second material is about 7.0 g/cm³ toabout 8.5 g/cm³. According to one aspect of the invention, the secondmaterial has a density of about 7.5 g/cm³ to about 8.1 g/cm³. Forexample, the density of the second material may be about 7.6 g/cm³ toabout 8.05 g/cm³. In one embodiment, the second material is any one ofthe alloys described above with regard to the first material.

The thickness of the crown may be from about 0.1 mm to about 1.0 mm. Inone embodiment, the thickness of the crown is about 0.2 mm to about 0.8mm. In still another embodiment, the thickness of the crown is about 0.4mm to about 0.6 mm. In yet another embodiment, the thickness of thecrown is about 0.5 mm.

In another embodiment of the invention, co-forging may be used to formthe high density materials, e.g., the first and second materials, forthe club head body member and optional crown. For example, a titaniumbar may be drilled and inserted with a higher density material (such assteel). Any suitable method of inserting the higher density material iswithin the scope of the invention, but press fitting is preferred. Onceinserted, the hole is welded shut and the bar is forged into the desiredshape. The high density material will flow with the titanium such thatcomponents formed using this method will have the modulus slightlyhigher than titanium, but densities ranging from about 6.0 g/cm³ toabout 9.0 g/cm³, preferably about 7.0 g/cm³ to about 8.5 g/cm³, morepreferably about 7.5 g/cm³ to about 8.1 g/cm³, and even more preferablyabout 7.6 g/cm³ to about 8.05 g/cm³. The components formed in thismanner can be welded together to form a club head.

In one embodiment, the face is formed from a third material that has adensity lower than the density of the first (and second) material usedto form the club head body member. The face may be formed from wroughtsheet by stamping or stamping and machining. The third material may havea density ranging from 3.5 g/cm³ to about 5.5 g/cm³. In one embodiment,the density of the third material is about 4.0 g/cm³ to about 5.5 g/cm³.According to one aspect of the invention, the third material has adensity of about 4.1 g/cm³ to about 5.1 g/cm³. In one embodiment, thethird material has a density at least about 30 percent less than thedensity of the first (and second) material. In another embodiment, thethird material has a density at least about 35 percent less than thedensity of the first (and second) material. In still another embodiment,the third material has a density at least about 40 percent less than thedensity of the first (and second) material.

In one embodiment, the third material is selected from the groupconsisting of Ti-6-4, SP-700, Ti-5111, and TCX11. In another embodiment,the third material is selected from the group consisting of Ti-15-3-3-3,Beta C, DAT 51, and DAT 55. In yet another embodiment, the face insertis formed from two or more components, each component formed from adifferent material selected from the group consisting of Ti-6-4, SP-700,Ti-15-3-3-3, Beta C, DAT 51, and DAT 55.

The thickness of the face insert is less than about 1.0 mm. In oneembodiment, the face insert is less than about 0.8 mm. In anotherembodiment, the face insert is about 0.6 mm or less. In still anotherembodiment, the face insert is about 0.5 mm or less.

The face insert (and crown if separate from the club head body member)may be joined together with the club head body member (in the respectivecavities) via welding, diffusion brazing, roll bonding, diffusionbonding, liquid interface diffusion (LID) bonding, or combinationsthereof In one embodiment, the face (and crown) insert may be joined tothe club head body member via welding. The type of welding used to joineach insert to the club head body member may be the same for bothinserts or different. As would be appreciated by those of ordinary skillin the art, the type of welding used to join the components together maybe any suitable welding that results in a joined product with the leastweld material at the joints and heat affected zones. In this aspect,suitable types of welding for use with the present invention include,but are not limited to, laser welding, plasma welding, TIG welding, MIGwelding, or combinations thereof In one embodiment, the type of weldingused to join either or both of the crown and face components may belaser welding, plasma welding, or combinations thereof. Without beingbound to any specific theory, laser and plasma welding reduces theamount of material added at the joint and result in smaller heataffected zones (as compared to TIG welding).

In another embodiment, the face insert may be joined with the club headbody member using roll bonding, diffusion bonding, diffusion brazing,LID bonding, or combinations thereof. If additional components are used,such as a skirt and a sole that are separate from the club head bodymember, these components may be stamped or machined into the desiredshape and welded to the club head body member using any suitable weldingmethod as described above.

FIG. 5 shows a portion of a golf club head 50 of the present invention.In the illustrated embodiment, the club head body member 60 is formedfrom a first material having a density ranging from about 6.0 g/cm³ toabout 9.0 g/cm³. The crown 70 may be formed in a unitary fashion withthe club head body member 60. In the alternative, the crown 70 may beformed separately from the club head body member 60 and from a secondmaterial that can be the same or different from the club head bodymember 60. The face insert 80 is formed from a third material and, morespecifically, a low density titanium alloy. In one embodiment, the clubhead body member 60 is further separated into components, e.g., a skirtand a sole, that are formed as separate pieces from the same ordifferent materials from each other and the main portion of the clubhead body member 60. In FIG. 5, the hosel and shaft are shown, but notconsidered to be part of the club head body member.

The golf club constructions described above may be employed in awood-type golf club. For a metal wood such as a driver or a fairwaywood, the club head has a volume of about 100 cc to about 460 cc.Preferably, the volume of a metal wood club head is at least about 250cc. According to one aspect of the invention, the volume for a hybridclub is between about 100 cc and about 200 cc. In one embodiment, thevolume for a hybrid club is between about 125 cc and 150 cc. In oneembodiment, the volume of a hybrid club according to the presentinvention may be less than 130 cc.

Finishing touches, e.g., painting and sanding, may optionally beperformed for aesthetic purposes.

Although the present invention has been described with reference toparticular embodiments, it will be understood to those skilled in theart that the invention is capable of a variety of alternativeembodiments within the spirit of the appended claims. For example, golfclub heads in accordance with examples of this invention may includestill additional features, if desired, including features that are knownand used in the art. For example, a golf club head according to theinvention may include a weighting system that is permanently mounted tothe club head body member, e.g., on an interior or exterior of the clubhead body, extending from the exterior to the interior of the club headbody (e.g., through a weight port), etc., or, in the alternative, aweighting system that includes weight member(s) that are movably and/orremovably mounted with respect to the club head body member usingstructures and techniques that are known and used in the art (e.g., byscrew or other mechanical connector attachments, by sliding attachments,etc.). Alternately, the sole may include one or more cavities that arecapable of accommodating inserts having variable weights. In addition,golf clubs according to the invention may include one or more of: (a) ashaft member engaged with the club head body; (b) a grip member engagedwith the shaft, and/or (c) a handle member engaged with the club headand/or the shaft. These additional elements of the golf club structuremay be included in the overall club structure in any desired mannerwithout departing from this invention, including in conventional mannersthat are known and used in the art (e.g., the shaft may be engaged withthe club head body member via an external hosel member, via an internalhosel member, through an opening provided in the club head, viaadhesives, and/or via mechanical connectors.

1. A golf club head, comprising: a first portion comprising a body defining an inner volume, a sole, a crown, and a skirt, wherein the first portion comprises a first material having a first density and a first weight, wherein the first material comprises an alloy comprising titanium, zirconium, or a combination thereof, and wherein the first density ranges from about 7 g/cm³ to about 8.5 g/cm³; and a second portion comprising a face, wherein the second portion comprises a second material having a second density less than the first density, wherein the second density is at least about 30 percent less than the first density.
 2. The golf club head of claim 1, wherein the first material comprises a binary titanium-zirconium alloy.
 3. The golf club head of claim 2, wherein the binary titanium-zirconium alloy comprises about 25 percent to about 75 percent by weight Zr.
 4. The golf club head of claim 2, wherein the binary titanium-zirconium alloy comprises about 10 percent to about 19 percent by weight Zr.
 5. The golf club head of claim 1, wherein the second density ranges from about 4 g/cm³ to about 5.5 g/cm³.
 6. The golf club head of claim 1, wherein the second material comprises titanium alloy.
 7. A golf club head, comprising: a first portion comprising a body defining an inner volume, a sole, a crown, and a skirt, wherein the first portion comprises a first material having a first density and a first weight, wherein the first material comprises a binary titanium or zirconium alloy, and wherein the first density ranges from about 6 g/cm³ to about 9 g/cm³; and a second portion comprising a face, wherein the second portion comprises a second material having a second density less than the first density.
 8. The golf club head of claim 7, wherein the first material comprises a binary titanium alloy selected from the group consisting of Ti-Zr, Ti-Hf, Ti-Mo, Ti-Ta, Ti-Nb, and Ti-Cr alloy.
 9. The golf club head of claim 7, wherein the first material comprises a binary zirconium alloy selected from the group consisting of Zr-W, Zr-Hf, and Zr-Ta.
 10. The golf club head of claim 7, wherein the second density ranges from about 3.5 to 5.5 g/cm³.
 11. The golf club head of claim 7, wherein the second material comprises titanium alloy.
 12. The golf club head of claim 7, wherein the second portion has a thickness of less than about 1.0 mm.
 13. A golf club head, comprising: a first portion comprising a body defining an inner volume, a sole, a crown, and a skirt, wherein the first portion comprises a first material having a first density and a first weight, wherein the first material comprises an alloy comprising titanium, zirconium, or a combination thereof, and wherein the first density ranges from about 6 g/cm³ to about 9 g/cm³; and a second portion comprising a face, wherein the second portion comprises a second material having a second density less than the first density by at least about 30 percent.
 14. The golf club head of claim 13, wherein the first material comprises a binary titanium alloy.
 15. The golf club head of claim 14, wherein the binary titanium alloy is selected from the group consisting of Ti-Zr, Ti-Hf, Ti-Mo, Ti-Ta, Ti-Nb, and Ti-Cr alloy.
 16. The golf club head of claim 14, wherein the binary titanium alloy comprises about 25 percent to about 75 percent by weight Zr.
 17. The golf club head of claim 13, wherein the first density ranges from about 7.5 g/cm³ to about 8.1 g/cm³.
 18. The golf club head of claim 13, wherein the second density ranges from about 3.5 to 5.5 g/cm³.
 19. The golf club head of claim 18, wherein the second density ranges from about 4.1 to 5.1 g/cm³.
 20. The golf club head of claim 13, wherein the second density is less than the first density by at least about 40 percent. 